Respiratory quotient is zero in succulent plants. Why ?

Explanation

In some succulent plants like opuntia , Bryophyllum, carbohydrate are partially oxidised to organic acid particularly malic acid without corresponding release of `CO_2` but `O_2` is consumed hence the RQ value will be zero .
`2C_6H_(12)O_6+3O_2 to underset("malic acid")(3C_4H_6O_5+3H_2O)+"Energy Glucose "`
RQ of glucose in `=("Zero molecule of " CO_2)/(3 "molecules of" CO_2)=0` (Zero) succulents